The invention relates to a wide-band phase shifter comprising a first and second branch arranged in parallel and receiving the same input signal at their inputs and producing a first and a second output signal at their outputs, these output signals being phase-shifted with respect to each other by a given angle, the first branch comprising a first phase shift module producing a phase shift as a function of a first control signal, said control signal being processed by a negative feedback loop comprising a phase-sensitive detector and receiving said first and second output signals.
A phase shifter of this type is known from the Article published by Al-ARAJI et al in the magazine "The Radio and Electronic Engineer" Vol. 50, no. 3, pages 107-112, March 1980, entitled "Frequency-independent analog phase-shift network technique using field effect transistors".
This article describes a phase shifter for low frequencies which can be used in the frequency band of 20-80 kHz for producing a 90.degree. phase shift between the two may be chosen to be within a range of .+-.20.degree. around the value of 90.degree..
Such a phase shifter has drawbacks which are particularly due to the fact that the phase shift between the two output signals is produced by phase-shifting network arranged in one of the two branches, while the other branch comprises a resistive network. The result is that the amplitudes at the two outputs cannot be equalized very accurately in a large range of frequencies.